I travel pretty light, I think:

Small seat bag: 2 tubes, 3 CO2 cartridges plus CO2 dispenser (what do you calll that thing?), multi tool, 2 tire levers, a couple cut up pieces of old tire to use as boots if needed, insurance card, $5.

Jersey Pockets: cell phone and money/ATM card in a baggie, food (amount and type depends on length of ride. For a ride under 50 miles, I usually don't bring any food.), short finger gloves if I start with long, any discarded clothing, rain jacket (if it looks threatening)

For a double century, long self-supported ride or Death Ride I _may_ bring a camelback. I usually don't. I have stopped using the Bento box unless the ride is long and flat (like this race I do in Tucson every year) as it really throws off my standing climbing.